The objectives of this study are to develop improved methods for the diagnosis and control of mammalian microsporidosis. This will be accomplished by the development of more sensitive, more reliable serological tests, the comparison of antigens obtained from a variety of mammalian microsporida and the biological and ultrastructural characterization of mammalian and invertebrate microsporidan isolates. BIBLIOGRAPHIC REFERENCE: Pakes, S.P.; Shadduck, J.A.: Fine structure of Encephalitozoon cuniculi from rabbits, mice and hamsters. Jr. Protozool. 22:481-488, 1975.